Retractable cord reels have been used in various applications to retractably store various types of wires, cords and cables. Typically, a reel might have a stationary end and a retractable end. The retractable end is typically wound on a rotating spool within the cord reel which carries a wire or cable capable of extension from and retraction back into the reel as the cord is unwound from then rewound back onto the rotating spool. The stationary end does not move during extension or retraction. Such a configuration reduces the mess typically associated with loose wires, as well as dangers related to loose cords which can, for example, become damaged creating electrical hazards or get in the way such as becoming a tripping hazard.
One type of prior art cord reel uses electrical contacts to achieve electrical continuity between the retractable cord carried on the rotating spool and the stationary cord which is typically attached to the stationary cord reel housing. These electrical contacts can slide as in common brush and slip ring type cord reels, or they can provide contact only when the spool is locked from rotation as described in U.S. Pat. No. 8,123,010 with inventors Richard Skowronski et al. The sliding contacts in a brush and slip ring cord reel can corrode, wear out, accumulate dirt or encounter other problems that may interfere with proper conduction of electricity or electrical signals. This is particularly a problem at low voltages where electricity is unable to arc through a small gap or dirt and result in an open circuit. Cord reels such as shown in U.S. Pat. No. 8,123,010 with inventors Richard Skowronski et al, which have contacts on a ratchet that engage only when the spool is locked from rotation, avoid some of the wear and dirt accumulation issues but they do not provide continuous continuity during extension and retraction of the retractable cable. Additionally, both the brush/slip ring cord reels and the contacts-on-ratchet cord reels can potentially cause sparks as the contacts rub which can be a problem in wet or potentially explosive environments.
Another type of cord reel can maintain continuous electrical continuity between the rotating spool and the stationary housing without any moving electrical contacts. This type of cord reel instead uses a dedicated internal flat cable to connect the rotating spool with the stationary housing. The internal cable has a flat configuration and winds from a loose coil to a tight coil as the spool is rotated, and then unwinds from a tight coil to a loose coil as the spool is rotated back. The flat cable is routed from a flat cable coiling area through an axial opening in a radial wall of the spool to the spool interior and connects to a round retractable cord. Examples of this type of cord reel can be seen in U.S. Pat. No. 5,535,960 with inventors Richard Skowronski et al and U.S. Pat. No. 5,094,396 with inventor Paul C. Burke.
A variation of the internal coil type cord reel has an internal flat cable coil that begins tightly coiled when the retractable cord is fully retracted, and uncoils when the retractable cord is extended. As the internal coil becomes fully unwound, continued rotation of the spool caused by additional extension of the retractable cord causes the internal cable to flip and switch direction and begin coiling in the opposite direction. When the retractable cord reaches full extension, the internal cable is tightly wound on the center of the spool in a direction opposite the direction at full retraction. The flat cable is typically routed through an opening in the spool wall to an internal chamber inside the spool where the cable transitions from a flat to a round configuration. An example of this type of cord reel can be seen in U.S. Pat. No. 6,372,988 with inventors Paul C. Burke et al. The advantage of this type of cord reel is that for a given size coil of internal cable, the number of turns of the spool is nearly doubled, greatly increasing the length of retractable cord that can be coiled on the spool. Unfortunately these cord reels have a very short service life because the internal cable is forced to bend sharply back and forth as the retractable cord is extended and retracted, resulting in early failure of the internal cable.
A new variation of this cord reel with a flipping internal cable is described in U.S. Pat. No. 8,387,763 with inventors Paul C. Burke et al. Here a rotating aperture, also called a rotating ferrule, is mounted to the axial opening in the radial wall of the rotating spool. The rotating aperture is entirely, or nearly entirely in the flat cable expansion chamber and rotates about its own axis such that as the internal flat cable flips from one coil direction to the other, the ferrule rotates to accommodate the flipping of the flat cable. The flat cable is routed through the aperture in the rotating aperture to the interior of the spool. This rotating ferrule eliminates the sharp bending of the internal flat cable, greatly increasing service life.